ML20002B343
| ML20002B343 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 10/24/1980 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Kay J YANKEE ATOMIC ELECTRIC CO. |
| References | |
| TASK-06-04, TASK-6-4, TASK-RR NUDOCS 8012110377 | |
| Download: ML20002B343 (8) | |
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!S to Mr. James A. Kay Senior Engineer-Licensi.s Yankee Atomic Electric Company 25 Research Drive Westborough, Massachusetts 01581
Dear Mr. Kay:
RE: SEP TOPIC VI-4 ELECTRICAL, INSTRUMENTATION AND CONTROL ASPECTS OF THE OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION (YANKEE-ROWE)
Enclosed is a copy of our evaluation of Systemath evaluation Program Topic VI-4, Electrical. Instrumentation and Control Aspects of the Override of Containment Purge Valve Isolation. This assessment compares your facility, as described in Docket No. 50-29, with the criteria currently used by the regulatory staff for licensing new facilities.
Please inform us if your as-built facility differs from the licensing basis assumed in our assessment within 60 days of receipt of this letter.
This evaluation will be a basic input to the integrated safety assessment for your facility unless you identify changes needed to reflect the as-built conditions at your facility. This topic assessment may be revised in the future if your facility design is changtd or if NRC criteria relating to this topic is modified before the integrated assessment is completed.
Sincerely, J
Dennis M. Crutch ield, f[ief Operating Reactors Branch #5 Division of Licensing
Enclosure:
Completed SEP Topic VI-4 cc w/ enclosure:
See next page 0
8012110 377 7
Mr. Janes A. Kay October 2'-
1980 cc Mr. Janes E. Tribble, President Yankee Atomic Electric Conpany 25 Research Drive Westborough, Massachusetts 01581 Greenfield Connunity College 1 College Drive Greenfield, Massachusetts 01301 Chairnan Board of Selectmen Town of Rowe Rowe, Massachusetts 01367 Energy Facilities Siting Council 14th Floor One Ashburton Place Boston, Massachusetts 02108 Director, Tc '<'eical Assessnent Division Office of Radiation Programs (AW-459)
U. S. Environmental Protection Agency Crystal Mall #2 Arlington, Virginia 20460 U. S. Environmental Protection Agency Region I Office ATTN: EIS C0ORDINATOR JFK Federal Building Boston, Massachusetts 02203 Resident Inspector Yankee Rowe Nuclear Power Station c/o U.S. NRC Post Office Box 28 Monroe Bridge, Massachusetts 01350 l
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SEP TECHNICAL EVALUATION T0FIC VI-4 ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OF THE OVERRIDE JF CONTAINMENT PURCE VALVE ISOLATION YANKEE R0WE NUCLEAR STATION Docket No. 50-29 I
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CONTENTS
1.0 INTRODUCTION
g 2.0 EVALUATION OF YANKEE R0WE NUCLEAR STATION' 1
2.1 Review Guidelines 1
2.2 Containment Ventilation Isolation Circuits Design Description.
2 2.3 Containment Ventilatien Isolation System Design Evaluation 3
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4.0 REFERENCES
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.a SEP TECHNICAL EVALUATION TOPIC VI-4 ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OF THE OVr.K.dIDE OF CONTAINMENT PURCE VALVE ISOLATION YANKEE ROWE NUCLEAR STATION
1.0 INTRODUCTION
Based on the information supplied by Yankee Atomic Electric Com-pany (YAEC), this report addresses the electrical, instrumentation, and control aspects of Containment Ventilation Isolation (CVI).
Instances have been reported where automatic closure of contain-ventilation (purge isolation) valves would not occur, if needed, ment because the actuation signals were manually overridden (blocked) during normal plant operation.
Lack of proper management controls, proced-ural inadequacies, and circuit design deficiencies contributed to these instances. These events also brought into question the mechanical operability of the valves.
These events were determined by the Nuclear Regulatory Commission (NRC) to be an Abnormal Occurrence (#78-05) and were reported to Congress.
The NRC is now reviewing the electrical override aspects and the mechanical operability aspects of containment purging for all operating reactors. On November 28, 1978, the NRC issued a letter, " Containment Purging During Normal Plant Operation"1' to all Boiling Water Reactor and Pressurized Water Reactor licensees to initiate a review of these systems. YAIC responded to this request for information in letters 2
3 dated January 8, 1979 and November 1, 1979.
2.0 EVALUATION OF YANKEE ROWE NUCLEAR STATION r
7.1 Review Guidelines The intent of this evaluation is to determine if the actuation signals for the CVI system meet the following NRC requirements:
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Guideline No. 1--In keeping with the requirements of General Design Criteria 55 and 56, the over-riding' of one type of safety acti;ation signal (e.g., radiation) should not cause the blocking of any other type of safety actuation signal (e.g.,
pressure) for those valves that have no function besides containment isolation.
1 2.
Guideline No. 2--Sufficient physical features (e.g.,
key lock switches) are to be provided to facilitate adequate administrative controls.
3.
Guideline No. 3--A system level annunciation of the
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overridden status should be provided for every safety system impacted when any override is active.
(See R.G. 1.47.)
Additionally, this review uses the following NRC design guidelines:
1.
Guideline No. 4--Diverse signals should be provided to initiate isolation of the containment ventilation system.
Specifically, containment high radiation, safety injection actuation, and containment high pressure (where containment high pressure is not a portion of safety injection actuation) should auto-matica11y initiate CVI.
2.
Guideline No. 5--The instrumentation and control systems provided to initiate the CVI should be designed and qualified as safety grade equipment.
3.
Guideline No. 6--the overriding or resettinga og the CVI actuation signal should not cause any valve or damper to change position.
2.2 Containment Ventilation isolation Circuits Design Description The Yankee Rowe unit has manual contain=ent purge valves. These valves are not a part of the automatic containment i, solation system.
The following definitions are given for clarity of use in this a.
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evaluation:
Overr ide :
the signal is still present, and it is blocked in order to perform a function contrary to the signal, t
Reset:
the signal has come and gone, and the circuit is being cleared in order to return it to the normal condition.
2
Section 3.6.1.1 of the Yankee Rowe Technical Specificatione requires containment integrity whenever the plant is in an operating mode or the main coolant pressure is greater or equal to 300 psig.3 Since the containment purge valves are part of the containment boundary, these I
valves are locked closed when containment integrity is r su td by Technical Specifications.
2.3 Containment Ventilation Isolation System Design Evaluation Guideline 1 allows no signal override to' prevent another safety actuation signal from functioning.
Because there are no signals which initiate closure of the CVI valves, this guideline does not apply to Yankee Rowe.
Guideline 2 requires reset and override switches to have physical provisions to aid in administrative control of reset and override switches. This guideline does not apply to the Yankee Rowe CVI system.
Guideline 3 requires that system level annunciation for wherever an override affects the performance of a safety system.
This guideline does not apply to the Yankee Rowe CVI system.
Guideline 4 requires that isolation of the CVI system be actuated by several diverse signals. The Yankee Rowe unit has only manual valves that are locked closed when the unit is in an operating mode. The NRC has no requirement that these valves be automatically operated; there-fore, the Yankee Rowe unit need not conform to this guideline.
Guideline 5 requires isolation actuation signals to be derived
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from safety grade equipment.
The Yankee Rowe unit has no present need to adhere to this guideline, as there are no isolation actuation signals.
Guideline 6 requires that resetting of isolation logic will not, of itself, automatically open the isolation valves.
This guideline is not applicable as the Yankee Rowe CVI system uses manual valves that 3
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cro r3 quired by Technical Sp;cification to b3 lock:d closed when the unit is in an operating condition.
3.0
SUMMARY
a The electrical, instrumentation, and control design aspects.of the containment ventilation isolation valves for the Yankee Rowe units were evaluated using the design guidelines stated in Section 2.1 of this report. Because the Yankee Rowe containment ventilation valves are locked shut as required by Technical Specifications, and have no auto-matic isolation signals or overrides, the NRC guidelines do not apply.
SEP Topic VII-2 will revies related engineered safety feature systems to insure that control logic and design is in accordance with IEEE Standard 279. The mechanical operability of the containment perge valves is being analyzed separately f rom this report.
4.0 REFERENCES
i 1.
NRC/ DOR letter, A. Schwencer, to all BWR and PWR license 2,
" Con-tainmetit Purging During Normal Plant Operation," dated 140 sember 28, 1978.
i 2
YAEC letter, D. E. Moody, to United States Nuclear Regulatory Commission, " Containment Purging During Normal Plant Operation,"
WYR 79-2, January 8,1979.
3.
YAEC letter, W. P. Johnson, to United States Nuclear Regulatory l
Commission, " Containment Purging and Venting During Normal Opera-tion," WYR 79-136, November 1, 1979, i
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